What's an upper return hose? shruggy

As I posted previously - "Lower hose with the old radiator could not possibly collapse (two short silicone elbows and a rigid 2" aluminum tube connecting them). Identical temp behavior with the new rad and a parts-store Gates hose." I suppose a collapse is possible but unlikely, given that the temperature reached, and the swings with the fans coming on and off, did not change one bit...

Anyhow if I have it off again, I'll put a spring in it. Thanks for the tip.

Flowkooler high-volume pump from Summit is allegedly coming today. I'll go take the old one out, I'm dying to know if I screwed up years ago and put a six-vane pump in it wink